Cleaning composition for removing



Patented Oct. 16, 1951 UNITED STATE CLEANING COMPOSITION FOR REMOVING ASPHALTIC COATINGS Jere C. Showalter, Baytown, Tex., assignor, by

mesne assignments, to Standard Oil Development Company, Elizabeth, N. J a corporation of Delaware No Drawing. Application October 12, 1949, Serial 'No. 121,051

Claims.

The present invention is directed to an improved composition for removing protective coatingsfrom surfaces on which such coatings are deposited. More particularly, the invention is directed to an improved composition for removing asphaltic coatings from surfaces designed to be protected by same.

Subsequent to cessation of hostilities in World War II many mobile units of the Armed Forces were sprayed with a protective coating composed of gilsonite, petroleum asphalt and petrolatum. When the mobile units were removed from storage it became necessary to remove the protective coating from the equipment before it could be used. At one storage point it was endeavored to remove the asphaltic coating from mobile equipment by spraying the equipment with a commercial detergent cleaner to which had been added kerosene. It was found that, to clean such equipment with this mixture, 16 to 20 man hours were required, depending on the size of the equipment to be cleaned. When it is considered that the Armed Forces may have thousands of such pieces of equipment in storage and sprayed with asphaltic coatings, it will become apparent that it is a tedious and timeconsuming operation to remove such equipment from storage and make it available for reuse. Furthermore, should a national emergency arise, it will be apparent that the equipment could not be put into use immediately without a loss of a vast amount of time.

It is, therefore, the main object of the present invention to provide an improved composition which will allow the removal of protective asphaltic coatings from equipment which has been sprayed with same. Another object of the present invention is to provide an improved composition which will readily dissolve asphaltic deposits. A still further object of the present invention is to provide an improved composition which may be sprayed on surfaces protected by asphalt and cause dissolution of same and allow the removal of the coating by washing with water.

The objects of the present invention may be achieved by spraying a surface coated with asphalt with an improved composition comprising an aromatic hydrocarbon solvent, low molecular weight alkali metal sulfonates, a lubricating oil fraction and high molecular weight alkali metal sulfonates, following which the coating which has been sprayed with my improved com-,

position is washed with hot water to remove same therefrom.

. :The invention may thus be briefly described as involving a composition comprising an aromatic hydrocarbon solvent boiling in the range between 300 and 500 F. in an amount in the,

range between 25% and by volume, low molecular weight alkali metal sulfonates having a.

The low molecular weight alkali metal 5111-.

fonates employed in the practice of the present invention are preferably the hydrophilic alkali metal sulfonates, While the high molecular weight alkali metal sulfonates may be termed hydrophobic. This terminology is relative, of

course, since it is to be understood that both,

the low and high molecular weight alkalimetal sulfonates are water soluble, but the hydrophilic alkali metal sulfonates are more readily soluble in water while the hydrophobic alkali metal sulfonates are more readily soluble in hydrocarbons. As a general rule, it may be stated that the hydrophilic alkali metal sulfonates may be obtained from the sludge acids resulting from the acid treatment of a hydrocarbon fraction of the proper boiling range whereas the hydrophobic alkali metal sulfonates are obtained from the hydrocarbons which have been treated with sulfuric acid or a sulfonation agent to cause sulfonation thereof. It is understood, of course, that the alkali metal sulfonates are formed by neutralization of the hydrophilic or hydrophobic sulfonc acids by treatment with an alkali metal hydroxide, as is well known to the art.

The low molecular weight alkali metal sulfonates are preferably in the molecular weight range of 325 to 400 and may be prepared by treatment with sulfuric acid of a hydrocarbon oil having a viscosity of 75 seconds Saybolt Universal (S. S. U.) at F. These sulfonates may contain a relatively large amount of the unsulfonated hydrocarbon but the presence of this oil in my improved composition is not detrimental and actually may aid in the cleaning effect obtained by same. These molecular weight sulfonates act as hydrophilic agents and as a detergent to aid in the removal of the asphaltic coating with hot water. As a specific example, given by way of illustration but not by way of limitation, a satisfactory low molecular weight alkali metal sulionate may be obtained by treating a solvent extract such as a phenol solvent;

-3 extract having a viscosity approximating that given with volume treats of 98% sulfuric acid followed by neutralization with sodium hydroxide and blowing with air. Such a composition may contain from. 10% to by volume of sulfonates.

The high molecular weight alkali metal sulfonates having a molecular weight preferably in the range from about 400 to 500 may be recovered from the manufacture of white oil having a viscosity of 500 S. S. U. atl00 F., wherein a treatment with strong sulfuric acid is involved. As a specific example of material finding satisfactory use in the present composition may be mentioned a mixture comprising 70% sodium sulfonate and of oil from white oil manufacture. These high molecular weight alkali metal sulfonates are hydrophobic and in combination with low molecular weight sulfonates may be used in the composition such that the mixture is in the border line of being hydrophilic and hydrophobic. The high molecular Weight alkali metal sulfonates are generally too viscous to be used alone as a detergent and aid in the control of the volatility of the aromatic hydrocarbon solvent which will be described further.

The aromatic hydrocarbon solvent employed in the present composition may be a relatively low boiling aromatic hydrocarbon having a flash point above about 113 F. and should contain at least 75% by volume of aromatics preferably boiling in the range of about 300 to about 500 F. The aromatic hydrocarbon employed in the present composition should be selected to be useful on surfaces that may be heated by the sun. An aromatic hydrocarbon fraction with a flash point of 150 F., 90% minimum aromatic content, 95% distilling over at 395 F., and a 425 F. maximum final boiling point gives very satisfactory results. The aromatic hydrocarbon solvent is the active ingredient which loosens the protective asphaltic coating from the equipment which it is protecting and penetrates therein, carrying with it the detergent. When aromatic hydrocarbon concentrates alone were used in an attempt to remove protective asphaltic coatings, the coatings were loosened but could not be removed by washing with hot water.

The hydrocarbon oil forming the component of my composition is preferably a lubricating oil :1

controlling the volatility of the aromaticsaswellas acting in part as a carrier for the various materials present in this composition.

In order to illustrate the practice of'my invention further, a composition containing thefollowing amounts of the various components may be found to give useful results:

Per cent by volume Aromatic hydrocarbons -1 25'to 75' Low molecular weight alkali metal sulfonates 5 to 33 High molecular weight alkali metal sulfonates 5th 12 Lubricating oil fractions 5 to 50 As a general rule, it will be desirable to provide a composition in which the aromatic hydrocarbon solvent and the low molecular weight alkali metal sulfonates are present in admixture in a major amount while the high molecular weight alkali metal sulfonates and oil fractions are present in admixture in a minor amount. It will be desirable that the amount of the aromatic hydrocarbon solvent be present in the composition in excess of the amount of the low molecular weight alkali metal sulfonates and it is also desirable that the lubricating oil fractions should be present in an amount in excess of the amount of high molecular weight alkali metal sulfonates.

As a specific example of a composition finding employment in the practice of the present invention, a preferred composition consisting of approximately by volume aromatic hydrocarbons having the characteristics given before, approximately 6% by volume of low molecular weight sodium sulfonates, approximately 7% by volume of high molecular Weight sodium sulfonates, and approximately 42% by volume of oil having the characteristics given before was made up and employed to clean mobile units which had been sprayed with a mixture of gilsonite, asphalt, and petrolatum. The units coated with the asphaltic mixture were sprayed with the foregoing composition, allowed to soak for-about 10 minutes, and then the coating was flushed off with hot water. It was found that the present composition allowed the cleaning time to be reduced by approximately In short, where heretofore from 16 to 20 hours time were consumed, by-

employing my composition the time for cleanin was reduced to from 4 to 5 hours. When it is considered thatone storage place alone may have on storage from 10 to 15,000 mobile units, it will be seen that the savings in time is considerable. In a period of national emergency, such a saving in time might mean the difference between success and disaster.

While the invention has been described and illustrated by employment of sodium sulfonates as the alkali metal sulfonates, it will be apparent to the skilled Workman that the potassium or lithium sulfonates may be used in lieu of the sodium sulfonates. However, the latter is to be preferred in view of their economic availability. Under some conditions, however, it may be desirable to use potassium or lithium sulfonates. Furthermore, while the invention has been described and illustrated by the employment of alkali metal sulfonates which have been recovered from petroleum hydrocarbon fractions which have been treated with sulfuric acid, it is to be understood that alkali metal sulfonates obtained from other sources may be used.

It is also to be understood that while the terms hydrophilic and hydrophobic have been used, this terminology is relative only and that the molecular weight of the alkali metal sulfonates will be controlling in determining the components of the composition. It is to be understood, however, that the alkali metal sulfonates of the range of molecular weights given will result in a composition being on the border line between hydrophilic and hydrophobic which is expressly required.

The invention has been described and illustrated by reference to cleaning asphaltic coatings from mobile units stored by the Armed Forces. It will be understood by the skilled workman that other protective coatings soluble in the present composition may be treated for removal therefrom from surfaces on which they are employed. For example, the asphaltic deposits may be removed from tanks and the like by the employment of my composition. Other uses will suggest themselves to the person skilled in the art.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful and to secure by Letters Patent is:

1. A composition adapted to be used in removing asphaltic bodies from surfaces coated with same consisting of an aromatic hydrocarbon solvent boiling in the range between 300 F. and 500 F. in an amount in the range between 25% and 75% by volume, hydrophilic low molecular weight alkali metal petroleum sulfonates having a molecular weight in the range between 325 and 400 in an amount in the range between 5% and 33% by volume, a hydrocarbon lubricating oil fraction having a viscosity in the range between 75 and 300 S. S. U. at 100 F. in an amount in the range between 5% and 50% by volume and hydrophobic high molecular weight alkali metal petroleum sulfonates having a molecular weight in the range between 400 and 500 in an amount in the range between 5% and 12% by volume.

2. A composition in accordance with claim 1 in which the alkali metal is sodium.

3. A composition in accordance with claim 1 in which the alkali metal is potassium.

4. A composition in accordance with claim 1 in which the alkali metal is lithium.

5. A composition adapted to be used in removing asphaltic bodies from surfaces coated with same which consists of approximately by volume of an aromatic hydrocarbon solvent having a flash point of 150 F. and a final boiling point of 425 F., approximately 6% by volume of hydrophilic sodium petroleum sulfonates having a molecular Weight in the range between 325 and 400, approximately 42% by volume of a hydrocarbon lubricating oil fraction having a viscosity in the range between and 300 S. S. U. at F., and approximately 7% by volume of hydrophobic sodium petroleum sulfonates having a molecular weight in the range between 400 and 500.

JERE C. SHOWALTER.

REFERENCES CITED The following references'are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,262,926 Edgar et a1. Nov. 18, 1941 2,481,268 Watson Sept. 6, 1949 FOREIGN PATENTS Number Country Date 350,505 Great Britain June 4, 1931 

1. A COMPOSITION ADAPTED TO BE USED IN REMOVING ASPHALTIC BODIES FROM SURFACES COATED WITH SAME CONSISTING OF AN AROMATIC HYDROCARBON SOLVENT BOILING IN THE RANGE BETWEEN 300* F. AND 500* F. IN AN AMOUNT IN THE RANGE BETWEEN 25% AND 75% BY VOLUME, HYDROPHILIC LOW MOLECULAR WEIGHT ALKALI METAL PETROLEUM SULFONATES HAVING A MOLECULAR WEIGHT IN THE RANGE BETWEEN 325 AND 400 IN AN AMOUNT IN THE RANGE BETWEEN 5% AND 33% BY VOLUME, A HYDROCARBON LUBRICATING OIL FRACTION HAVING A VISCOSITY IN THE RANGE BETWEEN 75 AND 300 S. S. U. AT 100* F. IN AN AMOUNT IN THE RANGE BETWEEN 5% AND 50% BY VOLUME AND HYDROPHOBIC HIGH MOLECULAR WEIGHT ALKALI METAL PETROLEUM SULFONATES HAVING A MOLECULAR WEIGHT IN THE RANGE BETWEEN 400 AND 500 IN AN AMOUNT IN THE RANGE BETWEEN 5% AND 12% BY VOLUME. 